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<FONT color="green">001</FONT>    package org.hackystat.sensor.xmldata.util;<a name="line.1"></a>
<FONT color="green">002</FONT>    <a name="line.2"></a>
<FONT color="green">003</FONT>    import java.text.DecimalFormat;<a name="line.3"></a>
<FONT color="green">004</FONT>    import java.text.NumberFormat;<a name="line.4"></a>
<FONT color="green">005</FONT>    import java.util.ArrayList;<a name="line.5"></a>
<FONT color="green">006</FONT>    import java.util.List;<a name="line.6"></a>
<FONT color="green">007</FONT>    <a name="line.7"></a>
<FONT color="green">008</FONT>    /**<a name="line.8"></a>
<FONT color="green">009</FONT>     * Provides an encoder for transforming a List instance containing strings into a single string<a name="line.9"></a>
<FONT color="green">010</FONT>     * (suitable for transmission via SOAP) and a decoder for reconstructing the List on the other side.<a name="line.10"></a>
<FONT color="green">011</FONT>     * Individual strings must be less than MAX_STRING_LENGTH, and the number of strings in the list<a name="line.11"></a>
<FONT color="green">012</FONT>     * must be less than MAX_NUM_STRINGS. Throws an exception if these maxima are exceeded, or if the<a name="line.12"></a>
<FONT color="green">013</FONT>     * List to be decoded contains a non-String element, or if the String to be decoded is not correctly<a name="line.13"></a>
<FONT color="green">014</FONT>     * formatted for decoding, or if the decoded string is not completely consumed by the decoding<a name="line.14"></a>
<FONT color="green">015</FONT>     * process.<a name="line.15"></a>
<FONT color="green">016</FONT>     * <a name="line.16"></a>
<FONT color="green">017</FONT>     * @author Philip M. Johnson<a name="line.17"></a>
<FONT color="green">018</FONT>     * @version $Id: StringListCodec.java,v 1.1.1.1 2005/10/20 23:56:44 johnson Exp $<a name="line.18"></a>
<FONT color="green">019</FONT>     */<a name="line.19"></a>
<FONT color="green">020</FONT>    public class StringListCodec {<a name="line.20"></a>
<FONT color="green">021</FONT>      /** The maximum length of any individual string to be encoded. */<a name="line.21"></a>
<FONT color="green">022</FONT>      public static final int MAX_STRING_LENGTH = 99999;<a name="line.22"></a>
<FONT color="green">023</FONT>      /** The DecimalFormat pattern for this max size. */<a name="line.23"></a>
<FONT color="green">024</FONT>      private static final String STRING_LENGTH_PATTERN = "00000";<a name="line.24"></a>
<FONT color="green">025</FONT>      /** The number of characters used to represent length field. */<a name="line.25"></a>
<FONT color="green">026</FONT>      private static final int STRING_LENGTH_FIELD_LENGTH = StringListCodec.STRING_LENGTH_PATTERN<a name="line.26"></a>
<FONT color="green">027</FONT>          .length();<a name="line.27"></a>
<FONT color="green">028</FONT>    <a name="line.28"></a>
<FONT color="green">029</FONT>      /** The maximum number of strings that can be encoded. */<a name="line.29"></a>
<FONT color="green">030</FONT>      public static final int MAX_NUM_STRINGS = 9999;<a name="line.30"></a>
<FONT color="green">031</FONT>      /** The DecimalFormat pattern for this max strings. */<a name="line.31"></a>
<FONT color="green">032</FONT>      private static final String NUM_STRINGS_PATTERN = "0000";<a name="line.32"></a>
<FONT color="green">033</FONT>      /** The number of characters used to represent the total number of encoded strings. */<a name="line.33"></a>
<FONT color="green">034</FONT>      private static final int NUM_STRINGS_FIELD_LENGTH = StringListCodec.NUM_STRINGS_PATTERN.length();<a name="line.34"></a>
<FONT color="green">035</FONT>    <a name="line.35"></a>
<FONT color="green">036</FONT>      /**<a name="line.36"></a>
<FONT color="green">037</FONT>       * Provides a thread-local version of DecimalFormat to support multi-threading.<a name="line.37"></a>
<FONT color="green">038</FONT>       * <a name="line.38"></a>
<FONT color="green">039</FONT>       * @author Philip Johnson<a name="line.39"></a>
<FONT color="green">040</FONT>       */<a name="line.40"></a>
<FONT color="green">041</FONT>      private static class ThreadLocalDecimalFormat extends ThreadLocal&lt;Object&gt; {<a name="line.41"></a>
<FONT color="green">042</FONT>        /**<a name="line.42"></a>
<FONT color="green">043</FONT>         * The initialization function.<a name="line.43"></a>
<FONT color="green">044</FONT>         * <a name="line.44"></a>
<FONT color="green">045</FONT>         * @return The DecimalFormat instance for this thread.<a name="line.45"></a>
<FONT color="green">046</FONT>         */<a name="line.46"></a>
<FONT color="green">047</FONT>        @Override<a name="line.47"></a>
<FONT color="green">048</FONT>        public Object initialValue() {<a name="line.48"></a>
<FONT color="green">049</FONT>          return NumberFormat.getInstance();<a name="line.49"></a>
<FONT color="green">050</FONT>        }<a name="line.50"></a>
<FONT color="green">051</FONT>      }<a name="line.51"></a>
<FONT color="green">052</FONT>    <a name="line.52"></a>
<FONT color="green">053</FONT>      /** The thread-local instance wrapper for the decimalFormat object. */<a name="line.53"></a>
<FONT color="green">054</FONT>      private static ThreadLocalDecimalFormat decimalFormat = new ThreadLocalDecimalFormat();<a name="line.54"></a>
<FONT color="green">055</FONT>    <a name="line.55"></a>
<FONT color="green">056</FONT>      /**<a name="line.56"></a>
<FONT color="green">057</FONT>       * Gets the thread-local DecimalFormat instance.<a name="line.57"></a>
<FONT color="green">058</FONT>       * <a name="line.58"></a>
<FONT color="green">059</FONT>       * @return The DecimalFormat instance for this thread.<a name="line.59"></a>
<FONT color="green">060</FONT>       */<a name="line.60"></a>
<FONT color="green">061</FONT>      private static DecimalFormat getDecimalFormat() {<a name="line.61"></a>
<FONT color="green">062</FONT>        return (DecimalFormat) decimalFormat.get();<a name="line.62"></a>
<FONT color="green">063</FONT>      }<a name="line.63"></a>
<FONT color="green">064</FONT>    <a name="line.64"></a>
<FONT color="green">065</FONT>      /**<a name="line.65"></a>
<FONT color="green">066</FONT>       * Encodes the passed list of strings into a single string and returns it.<a name="line.66"></a>
<FONT color="green">067</FONT>       * <a name="line.67"></a>
<FONT color="green">068</FONT>       * @param stringList a &lt;code&gt;List&lt;/code&gt; value<a name="line.68"></a>
<FONT color="green">069</FONT>       * @return a &lt;code&gt;String&lt;/code&gt; value<a name="line.69"></a>
<FONT color="green">070</FONT>       * @exception StringListCodecException If the list contains a non-String, or if the number of<a name="line.70"></a>
<FONT color="green">071</FONT>       *            strings in the list exceeds MAX_NUM_STRINGS, or if the length of any individual<a name="line.71"></a>
<FONT color="green">072</FONT>       *            string exceeds MAX_STRING_LENGTH.<a name="line.72"></a>
<FONT color="green">073</FONT>       */<a name="line.73"></a>
<FONT color="green">074</FONT>      public static String encode(List&lt;String&gt; stringList) throws StringListCodecException {<a name="line.74"></a>
<FONT color="green">075</FONT>        // Make sure we don't have too many list elements.<a name="line.75"></a>
<FONT color="green">076</FONT>        if (stringList.size() &gt; MAX_NUM_STRINGS) {<a name="line.76"></a>
<FONT color="green">077</FONT>          // Make darn sure someone hears about this even if the following exception is swallowed.<a name="line.77"></a>
<FONT color="green">078</FONT>          System.out.println("ERROR: StringListCodec max num strings exceeded.");<a name="line.78"></a>
<FONT color="green">079</FONT>          throw new StringListCodecException("String List exceeds " + MAX_NUM_STRINGS + " elements: "<a name="line.79"></a>
<FONT color="green">080</FONT>              + stringList);<a name="line.80"></a>
<FONT color="green">081</FONT>        }<a name="line.81"></a>
<FONT color="green">082</FONT>    <a name="line.82"></a>
<FONT color="green">083</FONT>        StringBuffer buff = new StringBuffer(computeBufferLength(stringList));<a name="line.83"></a>
<FONT color="green">084</FONT>    <a name="line.84"></a>
<FONT color="green">085</FONT>        // Encode the total number of list elements at the beginning of the string.<a name="line.85"></a>
<FONT color="green">086</FONT>        getDecimalFormat().applyPattern(NUM_STRINGS_PATTERN);<a name="line.86"></a>
<FONT color="green">087</FONT>        buff.append(((DecimalFormat) decimalFormat.get()).format(stringList.size()));<a name="line.87"></a>
<FONT color="green">088</FONT>    <a name="line.88"></a>
<FONT color="green">089</FONT>        // From now on, we encode using the following pattern.<a name="line.89"></a>
<FONT color="green">090</FONT>        getDecimalFormat().applyPattern(STRING_LENGTH_PATTERN);<a name="line.90"></a>
<FONT color="green">091</FONT>    <a name="line.91"></a>
<FONT color="green">092</FONT>        // Loop through the elements and add them to the string buffer.<a name="line.92"></a>
<FONT color="green">093</FONT>        for (String element : stringList) {<a name="line.93"></a>
<FONT color="green">094</FONT>          // replace all occurences of "\r", "\r\n" with "\n"<a name="line.94"></a>
<FONT color="green">095</FONT>          element = element.replaceAll("\r\n", "\n").replace('\r', '\n');<a name="line.95"></a>
<FONT color="green">096</FONT>    <a name="line.96"></a>
<FONT color="green">097</FONT>          // Second, make sure it's not too long.<a name="line.97"></a>
<FONT color="green">098</FONT>          if (element.length() &gt; MAX_STRING_LENGTH) {<a name="line.98"></a>
<FONT color="green">099</FONT>            // Make darn sure someone hears about this even if the following exception is swallowed.<a name="line.99"></a>
<FONT color="green">100</FONT>            System.out.println("ERROR: StringListCodec found a too long string.");<a name="line.100"></a>
<FONT color="green">101</FONT>            throw new StringListCodecException("String list contains too long string: " + stringList);<a name="line.101"></a>
<FONT color="green">102</FONT>          }<a name="line.102"></a>
<FONT color="green">103</FONT>    <a name="line.103"></a>
<FONT color="green">104</FONT>          // Now we add its size and the string itself to our buffer.<a name="line.104"></a>
<FONT color="green">105</FONT>          buff.append(getDecimalFormat().format(element.length()));<a name="line.105"></a>
<FONT color="green">106</FONT>          buff.append(element);<a name="line.106"></a>
<FONT color="green">107</FONT>        }<a name="line.107"></a>
<FONT color="green">108</FONT>        return buff.toString();<a name="line.108"></a>
<FONT color="green">109</FONT>      }<a name="line.109"></a>
<FONT color="green">110</FONT>    <a name="line.110"></a>
<FONT color="green">111</FONT>      /**<a name="line.111"></a>
<FONT color="green">112</FONT>       * Computes the exact length of the StringBuffer to allocate for this encoded string. This is<a name="line.112"></a>
<FONT color="green">113</FONT>       * worth the expense since StringBuffers are 16 chars by default and double each time they're<a name="line.113"></a>
<FONT color="green">114</FONT>       * exceeded, throwing away the old char array. A typical encoded string is gonna be 100 chars or<a name="line.114"></a>
<FONT color="green">115</FONT>       * more, which means throwing away 4-5 char arrays each time if we don't figure out the size in<a name="line.115"></a>
<FONT color="green">116</FONT>       * advance.<a name="line.116"></a>
<FONT color="green">117</FONT>       * <a name="line.117"></a>
<FONT color="green">118</FONT>       * @param stringList a &lt;code&gt;List&lt;/code&gt; value<a name="line.118"></a>
<FONT color="green">119</FONT>       * @return an &lt;code&gt;int&lt;/code&gt; value<a name="line.119"></a>
<FONT color="green">120</FONT>       */<a name="line.120"></a>
<FONT color="green">121</FONT>      private static int computeBufferLength(List&lt;String&gt; stringList) {<a name="line.121"></a>
<FONT color="green">122</FONT>        int length = NUM_STRINGS_FIELD_LENGTH;<a name="line.122"></a>
<FONT color="green">123</FONT>        for (String element : stringList) {<a name="line.123"></a>
<FONT color="green">124</FONT>          length += element.length() + STRING_LENGTH_FIELD_LENGTH;<a name="line.124"></a>
<FONT color="green">125</FONT>        }<a name="line.125"></a>
<FONT color="green">126</FONT>        return length;<a name="line.126"></a>
<FONT color="green">127</FONT>      }<a name="line.127"></a>
<FONT color="green">128</FONT>    <a name="line.128"></a>
<FONT color="green">129</FONT>      /**<a name="line.129"></a>
<FONT color="green">130</FONT>       * Decodes the passed string, returning a List of strings.<a name="line.130"></a>
<FONT color="green">131</FONT>       * <a name="line.131"></a>
<FONT color="green">132</FONT>       * @param encodedString The encoded list of strings.<a name="line.132"></a>
<FONT color="green">133</FONT>       * @return A new list of strings.<a name="line.133"></a>
<FONT color="green">134</FONT>       * @exception StringListCodecException If the passed encodedString is not encoded properly.<a name="line.134"></a>
<FONT color="green">135</FONT>       */<a name="line.135"></a>
<FONT color="green">136</FONT>      public static ArrayList&lt;String&gt; decode(String encodedString) throws StringListCodecException {<a name="line.136"></a>
<FONT color="green">137</FONT>        // replace all occurences of "\r", "\r\n" with "\n"<a name="line.137"></a>
<FONT color="green">138</FONT>        String newEncodedString = encodedString.replaceAll("\r\n", "\n").replace('\r', '\n');<a name="line.138"></a>
<FONT color="green">139</FONT>    <a name="line.139"></a>
<FONT color="green">140</FONT>        // Get the number of fields to be decoded.<a name="line.140"></a>
<FONT color="green">141</FONT>        int numFields;<a name="line.141"></a>
<FONT color="green">142</FONT>        try {<a name="line.142"></a>
<FONT color="green">143</FONT>          numFields = Integer.parseInt(newEncodedString.substring(0, NUM_STRINGS_FIELD_LENGTH));<a name="line.143"></a>
<FONT color="green">144</FONT>        }<a name="line.144"></a>
<FONT color="green">145</FONT>        catch (Exception e) {<a name="line.145"></a>
<FONT color="green">146</FONT>          throw new StringListCodecException("Error decoding numFields: " + newEncodedString, e);<a name="line.146"></a>
<FONT color="green">147</FONT>        }<a name="line.147"></a>
<FONT color="green">148</FONT>        // Make an array list to hold this number of elements.<a name="line.148"></a>
<FONT color="green">149</FONT>        ArrayList&lt;String&gt; stringList = new ArrayList&lt;String&gt;(numFields);<a name="line.149"></a>
<FONT color="green">150</FONT>        // Cursor always holds the index of next character to be processed in string.<a name="line.150"></a>
<FONT color="green">151</FONT>        int cursor = NUM_STRINGS_FIELD_LENGTH;<a name="line.151"></a>
<FONT color="green">152</FONT>        // Loop through the specified number of fields, extracting the field length and string,<a name="line.152"></a>
<FONT color="green">153</FONT>        // and incrementing cursor.<a name="line.153"></a>
<FONT color="green">154</FONT>        for (int i = 0; i &lt; numFields; i++) {<a name="line.154"></a>
<FONT color="green">155</FONT>          // First, get the field length.<a name="line.155"></a>
<FONT color="green">156</FONT>          int fieldLength;<a name="line.156"></a>
<FONT color="green">157</FONT>          String field;<a name="line.157"></a>
<FONT color="green">158</FONT>          try {<a name="line.158"></a>
<FONT color="green">159</FONT>            fieldLength = Integer.parseInt(newEncodedString.substring(cursor, cursor<a name="line.159"></a>
<FONT color="green">160</FONT>                + STRING_LENGTH_FIELD_LENGTH));<a name="line.160"></a>
<FONT color="green">161</FONT>          }<a name="line.161"></a>
<FONT color="green">162</FONT>          catch (Exception e) {<a name="line.162"></a>
<FONT color="green">163</FONT>            throw new StringListCodecException("Parse failed for field " + i + " and string "<a name="line.163"></a>
<FONT color="green">164</FONT>                + newEncodedString, e);<a name="line.164"></a>
<FONT color="green">165</FONT>          }<a name="line.165"></a>
<FONT color="green">166</FONT>    <a name="line.166"></a>
<FONT color="green">167</FONT>          // Second, extract that substring<a name="line.167"></a>
<FONT color="green">168</FONT>          cursor += STRING_LENGTH_FIELD_LENGTH;<a name="line.168"></a>
<FONT color="green">169</FONT>          try {<a name="line.169"></a>
<FONT color="green">170</FONT>            field = newEncodedString.substring(cursor, cursor + fieldLength);<a name="line.170"></a>
<FONT color="green">171</FONT>          }<a name="line.171"></a>
<FONT color="green">172</FONT>          catch (Exception e) {<a name="line.172"></a>
<FONT color="green">173</FONT>            throw new StringListCodecException("Could not extract field " + i + "from string "<a name="line.173"></a>
<FONT color="green">174</FONT>                + newEncodedString, e);<a name="line.174"></a>
<FONT color="green">175</FONT>          }<a name="line.175"></a>
<FONT color="green">176</FONT>    <a name="line.176"></a>
<FONT color="green">177</FONT>          // Third, add the field to the list, and increment the cursor.<a name="line.177"></a>
<FONT color="green">178</FONT>          stringList.add(field);<a name="line.178"></a>
<FONT color="green">179</FONT>          cursor += fieldLength;<a name="line.179"></a>
<FONT color="green">180</FONT>        }<a name="line.180"></a>
<FONT color="green">181</FONT>    <a name="line.181"></a>
<FONT color="green">182</FONT>        // Make sure we've consumed the entire string.<a name="line.182"></a>
<FONT color="green">183</FONT>        if (cursor != newEncodedString.length()) {<a name="line.183"></a>
<FONT color="green">184</FONT>          throw new StringListCodecException("Encoded string too long: " + newEncodedString);<a name="line.184"></a>
<FONT color="green">185</FONT>        }<a name="line.185"></a>
<FONT color="green">186</FONT>    <a name="line.186"></a>
<FONT color="green">187</FONT>        // We've extracted all of the fields, so now return the list.<a name="line.187"></a>
<FONT color="green">188</FONT>        return stringList;<a name="line.188"></a>
<FONT color="green">189</FONT>      }<a name="line.189"></a>
<FONT color="green">190</FONT>    }<a name="line.190"></a>




























































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